Veganism are the consumption practices of people advocating for animal liberation. It's not just about diet but also leather jackets/zoo visits etc. It's not like being part of an animal that imbues the individual molecules with some mystic energy that renders them off limits, it's that 99.99% of the time that obtaining these molecules in sufficient quantities requires overstepping boundaries of consent if not outright murder/slavery.

But I would consider scavenged meat for instance vegan, I still wouldn't because meat gives me the ick now, but I don't see how it is contrary to animal liberation (provided it doesn't disrupt other animals mourning rituals or something similar). Or rescued sheep still require shearing. It's not as brutal as farmers shearing and obviously not done with the wool in mind but rather the sheep. So the sheep are typically shorn(?) sooner than enslaved sheep and not as close to the skin, making "vegan wool" quite a bit harder to work with, but I would consider socks made out of that wool vegan.